The present invention relates to refractory components, and more particularly to well blocks and pocket blocks for use in metallurgical vessels for conveying molten metals.
The handling of high-temperature liquids, such as molten steel, requires special materials and techniques. Ladles used for handling molten steel are comprised of an outer metallic shell that is lined with a refractory material. The inner surface of the metallic shell is typically lined with one or more layers of a refractory brick that can withstand extremely high temperatures and harsh, abrasive conditions. A xe2x80x9cwell blockxe2x80x9d is disposed within the refractory lining of the metallurgical vessel. A well block is a refractory component having a bore therethrough to allow molten metal within the vessel to exit therefrom. The well block must be fixedly secured within the refractory lining to prevent the block from separating, i.e., floating, from the refractory lining on the bottom of the vessel during operation. To this end, it has been known to form well blocks having a step at the bottom thereof or to taper the well block from top to bottom to prevent the aforementioned floating or separation. It is also important that the well block be designed to retard penetration of molten metal along the interface between the well block and the refractory lining.
Steel ladles of the type heretofore described have a limited service life, after which the ladle must be relined. Advances in refractory brick technology have increased the service life of the refractory linings to where a brick lining may undergo 80 to 120 xe2x80x9cheats,xe2x80x9d i.e., use, before it is necessary to reline the ladle. However, conventional well blocks cannot withstand the repeated heating cycles of such a level of many ladle bricks now available. In this respect, conventional well blocks are formed by casting a refractory material, or by an air-ramming process. Air-rammed well blocks have a limited service life because it is difficult to obtain a block with good density by this process. A cast well block provides substantially better performance than an air-rammed block, but even a cast well block cannot provide the service life of newer refractory linings. As a result, multiple well block changes are typically required during the life of the refractory lining.
The present invention provides a well block having a service life that exceeds those of cast or rammed well blocks, and provides a well block that is designed to lock into a refractory lining and reduce metal penetration along the block-refractory lining interface.
In accordance with a preferred embodiment of the present invention, there is provided a well block for use in a refractory lining in a metallurgical vessel for holding molten metal. The well block is comprised of a body formed of a refractory material. The body has a top surface, a bottom surface, an inner surface defining a bore that extends through the body from the top surface to the bottom surface, and a double-curved outer surface having at least one peak or valley formed thereon.
In accordance with another aspect of the present invention, there is provided an isopressed well block for use in a refractory lining in a metallurgical vessel for holding molten metal. The well block has a body having a top surface, a bottom surface, an inner surface defining a bore that extends through the body from the top surface to the bottom surface. The refractory material is comprised of 5 to 95% by weight of a material selected from the group consisting of alumina in the form of tabular alumina, white fused alumina, brown fused alumina, bauxite or combinations of those materials, magnesium oxide (MgO), silica (SiO2), zirconium oxide (ZrO2), mullite (3 Al2O3.2 SiO2) and combinations thereof, 1 to 25% by weight carbon, and 0 to 15% of an antioxidant.
It is an object of the present invention to provide a well block for use in a refractory lining in a metallurgical vessel.
It is another object of the present invention to provide a well block as described above that has a service life exceeding conventional, cast or air-rammed well blocks.
It is another object of the present invention to provide a well block as described above that is isopressed.
It is another object of the present invention to provide a well block as described above that is less susceptible to separation from the refractory lining during use.
Another object of the present invention is to provide a well block as described above that minimizes penetration of molten metal along the refractory block-refractory lining interface.
Another object of the present invention is to provide a well block as described above having a bore diameter that minimizes turbulence and reduces wear from the flow of molten metal therethrough.
These and other objects will become apparent from the following description of a preferred embodiment and invention, taken together with the accompanying drawings.